SNOWTAM and NOTAM in Aviation: Decoder, Format, Validity and Examples Explained

A SNOWTAM is a specialized aviation notice that reports the surface condition of runways affected by snow, ice, slush, frost, or standing water. Issued under ICAO standards as a subset of the broader NOTAM system, a SNOWTAM provides pilots and dispatchers with the specific runway condition data needed to assess braking action, calculate contaminated runway performance, and make informed go or no-go decisions for winter operations. SNOWTAMs are sometimes spelled SNOTAM or snowtan in informal usage, though the correct ICAO designation is SNOWTAM.

A NOTAM, or Notice to Air Missions (previously Notice to Airmen), is the broader category of aviation notices that covers all significant changes to aeronautical facilities, services, airspace, procedures, and hazards. Where a SNOWTAM specifically addresses runway surface conditions during winter contamination events, a NOTAM covers a much wider range of operational information including runway and taxiway closures, navigational aid outages, temporary flight restrictions, and obstruction lighting failures.

For business aviation operators and flight dispatchers, understanding both SNOWTAM and NOTAM information before departure is a fundamental pre-flight trip planning requirement. This guide explains how SNOWTAMs are structured, how to decode the standard SNOWTAM format, what the validity period means in practice, and how to interpret real SNOWTAM examples for flight planning purposes.

Understanding NOTAM (Notice to Airmen) for Business Aviation Operations

NOTAMs serve as a communication tool to inform aviation personnel, including those involved in business jet operations, about crucial information related to aeronautical facilities, services, procedures, and potential hazards. These notices aim to enhance flight safety by ensuring that pilots, air traffic controllers, and other stakeholders in business aviation are aware of any changes or operational restrictions that may impact their operations.

NOTAMs consist of alphanumeric codes that convey specific information. The codes follow a standardized format to ensure clarity and consistency across the business aviation community. These codes include information about airport closures, temporary flight restrictions, runway obstructions, navigational aids status, airspace restrictions, and other relevant details specifically applicable to business jet operations.

For instance, a NOTAM might contain the following code: “D1234/23 – RWY 27 CLSD EXC ACFT WITH WINGSPAN < 79 FT.” In this example, “D1234/23” represents the NOTAM’s identification number, while “RWY 27 CLSD” indicates the closure of Runway 27. The subsequent statement “EXC ACFT WITH WINGSPAN < 79 FT” clarifies that the runway closure only applies to business jets with a wingspan less than 79 feet.

What Is a SNOWTAM in Aviation? Format, Validity and Real SNOWTAM Examples

SNOWTAMs are a specialized subset of NOTAMs that focus specifically on surface condition reports related to snow, ice, slush, frost, and standing water on operational runways. These reports are vital for pilots and aerodrome operators involved in business aviation to assess potential hazards and make informed decisions regarding flight operations.

SNOWTAMs are issued by aerodrome operators when significant changes occur in the surface condition of runways due to the presence of water, snow, ice, slush, or frost. Each new surface condition report triggers the issuance of a new SNOWTAM, which immediately cancels and replaces the previous one.

How to Read a SNOWTAM: A Step by Step Decoding Guide

Reading a SNOWTAM efficiently requires knowing which items to check first for flight safety relevance and which items provide supplementary context. The following step by step approach to SNOWTAM decoding covers the sequence that pilots and dispatchers typically use when evaluating a SNOWTAM for a planned arrival or departure.

Step 1: Check the identification number and time of observation. The identification number (the SNOWTAM serial number) tells you whether this is the most recent SNOWTAM for the aerodrome. A higher number means a more recent issuance. The Item B date and time group tells you exactly when the runway was assessed. Compare this to the current time: if the SNOWTAM is more than four hours old and conditions were poor at assessment, treat the data with caution and check whether a newer SNOWTAM has been issued.

Step 2: Identify the runway designator in Item C. Confirm that the SNOWTAM covers the runway you plan to use. If the airport has multiple runways, a separate SNOWTAM report section will exist for each runway in use.

Step 3: Read the runway condition codes in Item D. These single-digit codes for each third of the runway are the most operationally critical data point. Codes 0 and 1 indicate the worst conditions (dry compacted snow, ice, or wet ice); codes 5 and 6 indicate better conditions. If any third of the runway shows a code of 1 or 2, contaminated runway performance calculations are required before the flight can proceed.

Step 4: Check braking action and friction coefficient. The braking action assessment (GOOD, MEDIUM, POOR, or UNRELIABLE) tells you the assessed stopping performance on the runway. The friction coefficient in Item S gives a numerical value that can be used in aircraft performance calculations. POOR or UNRELIABLE braking action may require a longer landing distance than the runway can provide and should be cross-checked against the aircraft’s contaminated runway performance data.

Step 5: Check for reduced runway length in Item I. If the effective runway length has been reduced by snow clearance limits or temporary obstructions, the available landing distance will be less than the published runway length. This is one of the most commonly overlooked items in SNOWTAM decoding and can have a significant effect on whether a given aircraft type can legally land on the runway.

Step 6: Check taxiway and apron conditions in Items N, P, and R. Even if the runway is acceptable, poor taxiway or apron conditions may affect ground handling, fueling access, or the safety of taxiing a heavy or large-wingspan business jet.

SNOWTAM Validity Period

The SNOWTAM validity period is a maximum of eight hours from the time of observation recorded in Item B. This eight-hour maximum validity of SNOWTAM is set by ICAO standards to ensure that pilots and dispatchers are working from current runway condition data rather than outdated assessments. After eight hours, the SNOWTAM expires automatically regardless of whether conditions have changed.

In practice, when runway conditions are actively changing during a winter weather event, new SNOWTAMs may be issued every one to two hours as aerodrome operators re-survey the runway and update the surface condition report. Pilots planning arrivals at airports during active snowfall or icing conditions should check for the most recently issued SNOWTAM within the hour before their planned arrival,Operators should also confirm that aviation fuel uplift arrangements at the destination are not affected by ramp or apron conditions reported in SNOWTAM Items R and P, since poor apron conditions can delay or restrict fueling operations. since an assessment from six hours earlier may not reflect current braking action. The item B date and time group in the SNOWTAM identifies exactly when the runway was assessed, which is the reference point for evaluating whether the SNOWTAM is still operationally current for the planned flight.

 

To understand what a SNOWTAM looks like in practice, the following SNOWTAM example illustrates the standard format. Real SNOWTAM examples follow the same structure at every ICAO-compliant aerodrome worldwide:

‘SNOWTAM 1234/23 – RWY 09 FICON (M)4/3/2 – ICE BA GOOD, SNOW DEPTH 4MM, BRAKING ACTION MEDIUM, FRICTION COEFFICIENT 0.4 In this SNOWTAM example, ‘SNOWTAM 1234/23’ is the serial number, ‘RWY 09 FICON’ identifies the runway and indicates a Field Condition report, ‘(M)4/3/2’ represents the runway condition code for each third of the runway (medium ice layer), and the subsequent data gives the snow depth, braking action assessment, and friction coefficient measured on that runway at the time of observation. In this example, “SNOWTAM 1234/23” represents the SNOWTAM’s identification number. The subsequent information “RWY 09 FICON” indicates the focus on Runway 09 specifically for business jet operations. The code “(M)4/3/2” denotes the surface condition with a layer of ice at a medium thickness. The report also provides additional details such as the snow depth, braking action, and the friction coefficient, which helps business jet pilots assess the runway’s condition accurately.

SNOWTAM vs NOTAM: Key Differences and When Each Is Issued

Understanding the relationship between SNOWTAMs and NOTAMs is important for business aviation operators who review pre-departure notices as part of their standard flight planning process.

A NOTAM is the broader category. NOTAMs are issued for a wide range of aeronautical changes including runway and taxiway closures, navigational aid outages, airspace restrictions, military exercises, VIP movements, laser activity, parachuting operations, and temporary obstacle additions. A NOTAM can be in force for days, weeks, or months depending on the nature of the change it reports.

A SNOWTAM is a specific type of NOTAM that uses a dedicated standardized format to report runway surface conditions caused by winter contamination. Unlike a general NOTAM which uses free-text Q-code fields, a SNOWTAM uses a fixed item structure (Items A through T) that allows pilots and dispatchers to locate specific pieces of information, such as braking action or friction coefficient, in a consistent position every time regardless of which aerodrome issued the report. A SNOWTAM expires after a maximum of eight hours and is automatically superseded by any newer SNOWTAM for the same aerodrome.

The practical difference for business jet operators is this: NOTAMs require interpretation because their content varies widely. SNOWTAMs follow a fixed format that, once learned, can be read and acted on quickly. During winter operations, both need to be checked before every departure and arrival. The SNOWTAM tells you whether the runway can safely stop your aircraft in current conditions. The NOTAM tells you whether the runway, the navigation aids, and the airspace along your route are available and unencumbered.

SNOWTAM Decoder and NOTAM Decoder: How to Decode Aviation Notices for Business Operations

A SNOWTAM decoder or NOTAM decoder is the process, tool, or systematic reading method used to extract operational meaning from the alphanumeric codes in a SNOWTAM or NOTAM. Because SNOWTAMs and NOTAMs use standardized ICAO abbreviations and code formats, decoding them correctly requires familiarity with the specific item identifiers, condition codes, and abbreviations that each notice type uses. For SNOWTAM decoding, the items most critical to flight operations are the runway condition codes in Item D, the braking action assessment, the friction coefficient in Item S, and any reduced runway length reported in Item I. For NOTAM decoding, the Q-code fields, location indicators, and time validity codes carry the operational significance that dispatchers and pilots need to assess before departure.

Importance of Pre-flight Planning in Business Aviation

As part of pre-flight planning in business aviation, flight crews and NOTAM managers utilize a NOTAM decoder to retrieve and analyze relevant NOTAMs. This process ensures that they are aware of any potential operational impacts that may affect their business jet flights. Access to current NOTAMs can be obtained through airport Flight Briefing Facilities available to all aircraft operators. Additionally, some companies may have tailored access systems that provide access only to NOTAMs relevant to their specific business aviation operations.

NOTAMs for State and Government Officials’ Flights

Business aviation often involves flights carrying state and government officials. NOTAMs are issued for these flights, containing critical information related to security measures, airspace restrictions, or any specific procedures that must be followed during the operation. Flight permits for government and state flights often require coordination with the same authorities who issue the relevant NOTAMs, making integrated permit and NOTAM management essential for these operations. Utilizing a NOTAM decoder helps business jet operators and crews understand and comply with the specific requirements associated with these flights.

Managing Runway and Taxiway Closures in Business Aviation

In business aviation, efficient flight planning is essential to optimize schedules and minimize delays. NOTAMs regarding runway and taxiway closures play a vital role in this process. A NOTAM decoder allows business jet operators to access real-time information about such closures, enabling them to plan alternate routes, adjust arrival or departure procedures, and coordinate with ground handling teams at both the original and alternate destinations to ensure smooth operations.

Impact of Non-Operational Navaids on Business Aviation

Navaids are critical for navigation during flights. When a navigational aid becomes unserviceable, NOTAMs are issued to inform pilots and operators. In the context of business aviation, NOTAM decoders help identify and understand NOTAMs related to non-operational Navaids, such as VOR (VHF Omni-directional Range), ILS (Instrument Landing System), or DME (Distance Measuring Equipment). This information allows business jet crews to adjust their navigation plans, select appropriate alternate procedures, and work with their flight and route planning team to ensure navigational accuracy across the revised routing.

Ensuring Safety with Unserviceable Obstruction Lights

Maintaining situational awareness of obstacles and their lighting status is paramount in business aviation. NOTAM decoders assist in interpreting NOTAMs that highlight unserviceable obstruction lights. These lights can be present on tall structures, buildings, or construction equipment near airports. By accessing and comprehending the information provided by the NOTAM decoder, business jet pilots can plan their approaches, departures, and taxiing maneuvers safely, even in low-light or reduced-visibility conditions.

Handling Temporary Obstacles at Airfields in Business Aviation

Airfields occasionally encounter temporary obstacles, such as cranes or construction equipment, that may affect business aviation operations. NOTAMs are issued to inform operators and pilots about these obstacles. By employing a NOTAM decoder, business jet operators can identify and understand relevant NOTAMs related to temporary obstacles, allowing them to plan and adjust flight operations accordingly, ensuring safe takeoffs, landings, and ground movements.

SNOWTAM Format: Complete Guide to Sections A Through G (Aircraft Performance Items)

In business aviation operations, SNOWTAMs consist of various sections that provide essential information about runway conditions. One of these sections is the airplane performance calculation section. It includes the following eight items (A-G), which are filled out to ensure accurate assessment of aircraft performance:

 

• Item A (Aerodrome Location): This item indicates the specific location of the aerodrome where the runway is located.
• Item B (Date and Time of Observation): The eight-figure date/time group in UTC (Coordinated Universal Time) format represents the month, day, hour, and minute of the observation. It is important to record the assessment date and time for each runway, particularly when reporting on multiple runways.
• Item C (Runway Designator): The runway designator is inserted, representing the numerical value that appears in the lower part of the runway identifier. Only one runway designator is included for each runway being reported.
• Item D (Runway Condition Assessment): This item provides an indication of the runway condition for each third of the runway. A single-digit code is used to represent the condition of each third. The codes are determined based on factors such as the type, depth, and temperature of contaminants present on the runway. Higher numbers generally indicate better braking action.
• Item E (Runway Coverage Percentage): For each third of the runway, this item indicates the percentage of runway coverage. Information about runway conditions is provided only for runway thirds that have conditions other than “6” (indicating dry runway) in Item D and those with conditions other than “DRY” in Item G.

• Item F (Length of Loose Contaminant): This item specifies the length of loose contaminants in millimeters for each runway third. If conditions are not reported, ‘NR’ (Not Reported) is used. The SNOWTAM NR code appears in Item F when no loose contaminant measurement applies to that runway third, signaling to pilots that the field is either dry or that the contaminant present does not fall into the loose contaminant category requiring a depth measurement.

• Item G (Runway Condition Description): This item describes the condition of each third runway. It is mandatory to complete this item for each third. “NR” is used if there are no particular conditions to report. Compacted snow, dry, dry snow, dry snow on top of dry snow, dry snow on top of ice, frost, ice, slush, standing water, water on top of compacted snow, wet, wet ice, wet snow, wet snow on top of wet snow, and wet snow on top of ice are some words and phrases used to describe runway conditions.

 

SNOWTAM Format Continued: Situational Awareness Items I Through T Explained

The Situational Awareness section of SNOWTAMs in business aviation consists of 11 items (I-T) that provide crucial information regarding specific runway conditions. This section is excluded for elements where information is unavailable or when the conditions for publication have not been met.

• Item I (Reduced Runway Length): This item indicates the reduction in runway length, such as “RWY 14L REDUCED TO 3500.” It notifies pilots and operators that a portion of the runway is not available for use due to temporary obstructions or maintenance activities.
• Item J (Drifting Snow on the Runway): If there is drifting snow on the runway, this item is used to communicate the condition. For example, “DRIFTING SNOW” informs pilots about the presence of snow accumulation due to wind activity, which may impact runway operations.
• Item K (Runway Covered with Loose Sand): When the runway is covered with loose sand, this item is utilized. For instance, “RWY 14L LOOSE SAND” informs pilots about the sand covering the runway, which may affect aircraft performance and braking action.
• Item L (Runway Chemical Treatment): In cases where the runway has undergone chemical treatment, this item is used. For example, “RWY 14L CHEMICALLY TREATED” informs pilots that the runway has been treated with chemicals to mitigate ice or snow conditions.
• Item M (Snow Banks on the Runway): If there are snow banks present on the runway, this item is used to provide information. An example is “RWY 14L SNOW BANK L20 FM CL,” where “L20 FM CL” indicates a snow bank located 20 meters from the runway’s centerline. “LR” is used to indicate snow banks on both sides of the runway.
• Item N (Snow Banks on Taxiways): When there are snow banks on the taxiways, this item is used to convey the information. For instance, “TWY A SNOW BANK” indicates the presence of a snow bank on Taxiway A, which may affect taxiing operations.
• Item O (Snow Banks Adjacent to the Runway): This item refers to snow banks located adjacent to the runway as per the aerodrome snow plan. An example is “RWY 14L ADJ SNOW BANKS,” informing pilots of the presence of snow banks in close proximity to the runway.
• Item P (Taxiway Conditions): This item describes the condition of the taxiways. For example, “TWY B POOR” indicates that Taxiway B has poor conditions, such as snow, ice, or reduced friction.
• Item R (Apron Conditions): In this item, the condition of the apron is provided. For instance, “APRON WEST POOR” notifies operators about poor conditions on the western side of the apron area.
• Item S (Runway Friction Coefficient Measurement): If runway friction has been measured, this item is used. It specifies that an approved measurement device was used and indicates if there is an established program for runway friction measurement in place.
• Item T (Plain Language Remarks): This item allows for additional plain language remarks that are not covered by the previous items. It provides flexibility to include relevant information or observations regarding the runway conditions that are important for business aviation operations.

 

Best practices for SNOWTAM and NOTAM issuance in business aviation include timely and accurate reporting, standardized formats, precise identification, utilization of metric units, concise content, cross-checking with business operators. Following these practices ensures efficient communication of critical information, enhances situational awareness, and supports safe flight operations.

 

Just Aviation’s flight planning and trip support team monitors current NOTAMs and SNOWTAMs for every client departure, identifying runway closures, surface condition changes, and airspace restrictions before they affect the planned schedule. When a SNOWTAM indicates deteriorating braking action at the destination airport, or a NOTAM closes the planned runway, our team identifies alternative options and coordinates the operational changes needed to keep the flight on schedule. For business jet operators who need reliable pre-flight intelligence on both SNOWTAM and NOTAM status across global destinations, Just Aviation provides the monitoring and interpretation support that turns raw ICAO notices into actionable flight planning decisions.